BUG-2242: LLDP speaker as separate application.

 * Remove LLDPSpeaker and all related classes and methods from openflowplugin
 * Create separate LLDPSpeaker application
 * Replace usage of Timer with ScheduledExecutorService which use monotonic
   timer for delays instead of system time.
 * Decomposed LLDPSpeaker into several classes to improve unit testabilty
 * added lldp app to base distro

Change-Id: I997c74203af7461840c1c711355120b415995c06
Signed-off-by: Anton Frolov <anton.frolov@pacnet.com>
Signed-off-by: Michal Rehak <mirehak@cisco.com>